1. Field of the Invention
The present invention relates to a process for the desulfurization of sulfur-containing hydrocarbon oils. More particularly, it relates to hydrodesulfurization process wherein the hydrogen-containing treating gas comprises an added C1 to C4 alcohol.
2. Description of the Prior Art
Hydrodesulfurization processes in which water as a liquid or as a vapor is added to the hydrodesulfurization reaction zone are known, see for example U.S. Pat. Nos. 3,501,396; 3,753,894, and 3,720,602. Water addition to a hydrodesulfurization process can be costly due to the heat required to vaporize the water to steam and to heat it to reaction temperature. It is also difficult to vaporize large quantities of water smoothly without causing undue vibrations and pressure shock waves in the reaction vessel.
It has now been found that the addition of a C1 to C4 alcohol, preferably methanol, to the hydrodesulfurization process will overcome many of the difficulties involved in H.sub.2 O addition. Methanol, for example, has a lower surface tension and is more soluble than water in the hydrocarbon feed, and has a lower heat of vaporization.